This invention relates to color light modulators and more particularly to color modulators actuated by a MEMS actuator.
There are many applications for color light modulators that have high resolution and brightness, including applications in display of information for education, business, science, technology, health, sports, and entertainment. Some light modulators, such as oil-film projectors, liquid-crystal displays (LCD""s), digital light-mirror arrays, and deformographic displays, have been applied for large-screen projection. In the visible spectrum, light modulators, such as the reflective digital mirror arrays, have been developed with high optical efficiency, high fill-factors with resultant low pixelation, convenient electronic driving requirements, and thermal robustness. For gray scale variation, binary pulse-width modulation has been applied to the tilt of each micro-mirror. To vary color, such modulators typically have used either a sequential color wheel (rotating color filter) or multiple modulators with an individual stationary color filter being associated with each modulator. In the latter case, the various color images (e.g., red, green, and blue) are recombined optically. Both binary pulse-width modulation and synchronization of color information has been accomplished by off-chip electronics, controlling on- or off-chip drivers.
Diffractive light modulators and displays have also been developed, in which bright and dark pixels in a display are produced by controlling a diffraction grating at each pixel, effectively varying the grating frequency of each pixel by varying a gap between a thin film ribbon and a substrate surface. Typically, for color displays using this principle, three different gratings and three associated actuators have been required for each pixel.
Both micro-mirror and diffraction-grating types of modulators have used actuators based on micro-electro-mechanical-system (MEMS) techniques. MEMS actuators have also been employed in other applications such as micro-motors, micro-switches, and valves for control of fluid flow.
While the various color light modulators have found widespread success in their applications, there are still unmet needs in the field of color- and spatial-light-modulators, such as combining analog color modulation with high optical efficiency and close integration of color synchronization with each pixel modulator.